Almost blank subframe in carrier aggregation

Patent metadata

Field	Value
Publication number	US-9900882-B2
Application number	US-201715406009-A
Country	US
Kind code	B2
Filing date	Jan 13, 2017
Priority date	Oct 29, 2011
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

A base station transmits a message to a plurality of wireless devices in connected mode. The message comprises a subframe allocation bitmap indicating a plurality of subframes. The plurality of subframes comprises a plurality of almost blank subframes. During majority of symbols of an almost blank subframe of a base station, signals are transmitted at an almost blank subframe power level that is different from a transmit power during a non-almost blank subframe.

First claim

What is claimed is:

1. A method comprising:
transmitting, by a base station, a first message comprising a subframe allocation bitmap indicating a plurality of Almost Blank Subframes, wherein the plurality of Almost Blank Subframes consists of second, fourth, seventh, and ninth subframes of each radio frame in a plurality of radio frames;
transmitting, to a wireless device, a second message comprising:
a first measurement subframe allocation bitmap indicating a first plurality of measurement subframes of a primary carrier, wherein the first plurality of measurement subframes excludes the plurality of Almost Blank Subframes; and
a second measurement subframe allocation bitmap indicating a second plurality of measurement subframes of the primary carrier, wherein the second plurality of measurement subframes excludes the first plurality of measurement subframes; and

transmitting, by the base station, a first Almost Blank Subframe, wherein the first Almost Blank Subframe is transmitted at a power level that is lower than during a non-Almost Blank Subframe.

2. The method of claim 1 , wherein the first Almost Blank Subframe consists essentially of a common reference signal in a control region.

3. The method of claim 1 , wherein each radio frame in the plurality of radio frames is assigned a system frame number (SFN).

4. The method of claim 1 , wherein the first message further comprises:
a subframe allocation repetition period in terms of n radio frames, n being an integer greater than or equal to one; and
a subframe allocation offset i, i being an integer greater than or equal to zero.

5. The method of claim 4 , wherein the subframe allocation bitmap indicates a plurality of subframes in k frames, k being an integer and 1≦k≦n, the bitmap applying to subframes in k frames starting from frames whose SFN meets (SFN mod n=i) criterion.

6. The method of claim 4 , wherein the subframe allocation repetition period is 1, 2, 4, 8, 16, or 32 radio frames.

7. The method of claim 1 , wherein the base station broadcasts:
a system frame number represented by m bits;
the p most significant bits of the system frame number employing a plurality of subcarriers in the middle of a frequency band of a carrier; and
the (m−p) least significant bits of the system frame number by encoding control blocks in a physical broadcast channel over 2 (m−p) frames, wherein the (m−p) least significant bits are determined by sequential positions of the encoded control blocks.

8. A method comprising:
transmitting, by a base station, a first message comprising a subframe allocation bitmap indicating a plurality of Almost Blank Subframes, wherein the plurality of Almost Blank Subframes consists of third and eighth subframes of each radio frame in a plurality of radio frames;
transmitting, to a wireless device, a second message comprising:
a first measurement subframe allocation bitmap indicating a first plurality of measurement subframes of a primary carrier, wherein the first plurality of measurement subframes excludes the plurality of Almost Blank Subframes; and
a second measurement subframe allocation bitmap indicating a second plurality of measurement subframes of the primary carrier, wherein the second plurality of measurement subframes excludes the first plurality of measurement subframes; and

transmitting, by the base station, a first Almost Blank Subframe, wherein the first Almost Blank Subframe is transmitted at a power level that is lower than during a non-Almost Blank Subframe.

9. The method of claim 8 , wherein the second message further configures measurement subframes of a plurality of neighboring carriers for the wireless device.

10. The method of claim 8 , wherein the wireless device periodically reports channel state information for subframes indicated in the first measurement subframe allocation bitmap.

11. The method of claim 8 , wherein the wireless device periodically reports channel state information for subframes indicated in the second measurement subframe allocation bitmap.

12. The method of claim 8 , wherein the first Almost Blank Subframe consists essentially of a common reference signal in a control region.

13. The method of claim 8 , wherein each radio frame in the plurality of radio frames is assigned a system frame number (SFN).

14. The method of claim 8 , wherein the first message further comprises:
a subframe allocation repetition period in terms of n radio frames, n being an integer greater than or equal to one; and
a subframe allocation offset i, i being an integer greater than or equal to zero.

15. The method of claim 14 , wherein the subframe allocation bitmap indicates a plurality of subframes in k frames, k being an integer and 1≦k≦n, the bitmap applying to subframes in k frames starting from frames whose SFN meets (SFN mod n=i) criterion.

16. A method comprising:
transmitting, by a base station, a first message comprising a subframe allocation bitmap indicating a plurality of Almost Blank Subframes, wherein the plurality of Almost Blank Subframes consists of second, fourth and eighth subframes of each radio frame in a plurality of radio frames;
transmitting, to a wireless device, a second message comprising:
a first measurement subframe allocation bitmap indicating a first plurality of measurement subframes of a primary carrier, wherein the first plurality of measurement subframes excludes the plurality of Almost Blank Subframes; and
a second measurement subframe allocation bitmap indicating a second plurality of measurement subframes of the primary carrier, wherein the second plurality of measurement subframes excludes the first plurality of measurement subframes; and

transmitting, by the base station, a first Almost Blank Subframe, wherein the first Almost Blank Subframe is transmitted at a power level that is lower than during a non-Almost Blank Subframe.

17. The method of claim 16 , wherein the second message further configures measurement subframes of a plurality of neighboring carriers for the wireless device.

18. The method of claim 16 , wherein the wireless device periodically reports channel state information for subframes indicated in the first measurement subframe allocation bitmap.

19. The method of claim 16 , wherein the wireless device periodically reports channel state information for subframes indicated in the second measurement subframe allocation bitmap.

20. The method of claim 16 , further comprising:
transmitting, by the base station and in response to a decrease in traffic load of the base station by an amount greater than a first value, a third message comprising a second subframe allocation bitmap indicating a second plurality of Almost Blank Subframes, wherein the second plurality of Almost Blank Subframes consists of second, fourth, seventh, and ninth subframes of each radio frame in a second plurality of radio frames.

21. The method of claim 16 , further comprising:
transmitting, by the base station and in response to an increase in traffic load of the base station by an amount greater than a first value, a third message comprising a second subframe allocation bitmap indicating a second plurality of Almost Blank Subframes, wherein the second plurality of Almost Blank Subframes consists of third and eighth subframes of each radio frame in a second plurality of radio frames.

22. The method of claim 1 , wherein the second message further configures measurement subframes of a plurality of neighboring carriers for the wireless dev

Assignees

• Comcast Cable Comm Llc

Inventors

• Dinan Esmael Hejazi

Classifications

• H04W72/21

  in the uplink direction of a wireless link, i.e. towards the network · CPC title

• H04W72/23 Primary

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04W72/54

  based on quality criteria · CPC title

• H04W88/08

  Access point devices · CPC title

• H04W72/0446

  Resources in time domain, e.g. slots or frames · CPC title